# Find the System Index Multipliers for any system

System Index
A value that changes over time and affects the installation fee when you install a Manufacturing, Copying, Invention, ME Research or TE Research job in a particular solar system. This value is different for each system and job type. Click here to see the indexes for a system.
System Index Multiplier
An unchanging value based on the stations in a solar system that is used in the calculation of the System Indexes.

With the Crius expansion to EvE Online, CCP altered the industrial landscape, as documented in the Eve Industry - all you want to know dev blog. Recently, a crack team of research scientists investigated an anomaly uncovered by capsuleer "probag Bear", and discovered that Appendix 2 of that dev blog was both incorrect and incomplete. This API calculates System Index Multiplier using the actual effects of each station as uncovered by said crack team, and therefore provides the accurate value of the System Index Multipliers for any system in EvE, whether they contain NPC stations, conquerable stations or outposts. If you prefer to do the (fiddly) calculation youself, you can use this table containing the correct values of the effects for each station.

### Does the System Index Multiplier matter to me?

If you or your organisation set off so many build jobs that you cause an appreciable shift in one of a system's Manufacturing/Research Indexes, then the System Index Multipliers matter to you when you're deciding where to base your manufacturing and research operations.

The effect on Manufacturing Index of multiple accounts

shifting production from the red system to the blue system

If you are only setting off a few jobs every now and then, then you won't have much impact on the system's Manufacturing/Research Indexes (especially if there are others already building in the system). In this case, the System Index Multipliers aren't really relevant, and to minimise costs you should focus on the system Manufacturing or Research Indexes.

On the other hand, if you have several characters that are building or researching most of the time, you will notice that the System Index gradually creeps up for the first 28 days after you start building in a system. In the picture above, we see what happens to the System Index when a healthy number of accounts stop building in the red system, then after a couple of days start building in the blue system.

If your decision about where to build in came down to two systems that both had exactly the same Index, then you should choose the one with the lower Index Multiplier as that system will reach a lower peak after 28 days of building.

### I can't be fucked to read that dev blog, how's it work?

Industry job installation fees that you pay when you install any industry job get more expensive, the more other people are setting off jobs in the same system. But with the same number of people setting off identical jobs, different systems will end up with slightly different costs because of their System Index Multiplier. Note that the system Manufacturing/Copying/Invention/ME Research and TE Research Indexes shown in-game already take this multiplier into account, so to determine the fees you will pay for a given job, you only need to know the Index for that system and job type. However if you are evaluating production or research locations, then you can take into account both the current value of the Index and the Index Multiplier to estimate how much the Index will move as your production gears up.

### System Index formula

There aren't just errors in Appendix 2 from the blog, the given S ystem Index formula also generates different values to those we see in game! The correct formula is:

$\mathrm{system manufacturing index}=max\left(0.0001,\sqrt{\frac{\mathrm{system installed job-hours over the last 28 days}}{\mathrm{universe installed job-hours over the last 28 days}}}\right)×\mathrm{system index multiplier}$

This Index is calculated separately for each of the 5 manufacturing activities(Manufacturing, TE Research, ME Research, Copying, Invention). There are two Index Multipliers for each system - one that is used to calculate manufacturing indexes, and another one used to calculate indexes for each of the four science-based industry activities.

### System Index Multiplier calculation

The System Index Multiplier is the product of a value associated with each station in a system. Each station has one value for manufacturing, and another value for science/research jobs. These values are listed in Appendix 2 of the Eve Industry - all you want to know dev blog, however CCP missed out some info (e.g. Conquerable Station Refineries) and got some values wrong (e.g. some Warehouse NPC stations, Minmatar Outposts). The correct values (as far as our crack team of research scientists can determine) are listed in this handy pastebin.

## How does this API work then?

### Query a specific system

To use this API, simply request https://stop.hammerti.me.uk/api/index.multiplier/system/SYSTEM_ID where SYSTEM_ID is the id of a solar system (you can find this in the SDE or online). For example, if you access https://stop.hammerti.me.uk/api/indexmultiplier/system/30000142 you will receive some data in JSON format telling you Jita's two System Index Multipliers:

{
"30000142" : {
"manufacturing_index_multiplier": 0.638555082927557,
"research_index_multiplier": 0.753641941474902,
}
}


### Entire Universe

If you wish to download a list of every single system's Index Multipliers, simply use "all" instead of a system id: https://stop.hammerti.me.uk/api/indexmultiplier/system/all. This information should basically never change, so you shouldn't need to poll it regularly, but if for some weird reason you need to do this, make sure that your client has "Accept-Encoding: gzip" set and respect the Cache-Control header, as the "all" list is quite large.